Nature Photonics ( IF 31.241 ) Pub Date : 2020-09-14 , DOI: 10.1038/s41566-020-0688-8 Charlie-Ray Mann; Simon A. R. Horsley; Eros Mariani
Pseudo-magnetic fields generated in artificially strained lattices have enabled the emulation of exotic phenomena once thought to be exclusive to charged particles. However, they have so far failed to emulate the tunability of real magnetic fields because they are determined solely by the engineered strain configuration, rendering them fixed by design. Here, we unveil a universal mechanism to tune pseudo-magnetic fields for polaritons supported by a strained honeycomb metasurface composed of interacting dipole emitters/antennas. Without altering the strain configuration, we show that the pseudo-magnetic field strength can be tuned by modifying the surrounding electromagnetic environment via an enclosing cavity waveguide, which modifies the nature of the dipole–dipole interactions. Owing to the competition between short-range Coulomb interactions and long-range photon-mediated interactions, the pseudo-magnetic field can be entirely switched off at a critical cavity width, without removing the strain. Consequently, by varying only the cavity width, we demonstrate a tunable Lorentz-like force that can be switched on/off and a collapse and revival of polariton Landau levels. Unlocking this tunable pseudo-magnetism poses new intriguing questions beyond the paradigm of conventional tight-binding physics.